Sony is launching Resistance 3 for the PlayStation 3 today, kicking off the big fall video game launch season. The Sony exclusive is the first salvo in the battle between the game platforms that will occupy gamers for the next few months.

Resistance 3 is the sort of Sony exclusive that will keep loyal fans from defecting to more popular platforms such as the Xbox 360. If Sony and developer Insomniac Games have done their jobs right, the title will steal some of the time that gamers have to play other titles. And it will generate hundreds of millions of dollars in sales. Early reviews are coming in moderately strong at 86 out of 100 on review aggregator Metacritic.

One thing working in Sony’s favor is timing. Most expected blockbuster releases are coming out later in the season (although Eidos’ Deus Ex Human Revolution and Electronic Arts’ Madden NFL 12 have already shipped). Gears of War 3 debuts on the Xbox 360 on Sept. 20; Rage comes on Oct. 7; Batman Arkham City arrives Oct. 21; Uncharted 3 hits Nov. 1; Battlefield 3 arrives on Oct. 25; and Call of Duty Modern Warfare 3 comes on Nov. 8.

Resistance 3 will stand out because it is the final installment in a series that has played out entirely on the same console, so the developers at Insomniac Games have now had a chance to perfect their code on the PS 3 and correct past mistakes.

Resistance is based on an alternate universe set in the 1950s, where World War II didn’t happen because it was forestalled by the invasion of an alien race called the Chimera. The new game is set four years after the end of Resistance 2. The Chimera still have enough intelligence to surround you and flush you out of your position with grenades and flank attacks.

This installment features Joseph Capelli, one of the few survivors still hiding out and fighting in the American Midwest. He teams up with a Russian scientist to take the battle to the enemy in New York. The post-apocalyptic ruins of America are haunting, and the first-person shooting action is intense. The victorious Chimerans are already terraforming and cooling the planet.

I’ve had an early look at parts of the single-player and multiplayer games. The cool thing about Resistance has always been its diversity of weapons. My favorite has been the hand grenade that shoots out spikes in all directions. One of the new weapons is the Deadeye, a sniper rifle that has the ability to vaporize an enemy. The Mutator, meanwhile, fires a green cloud that leaves the enemy vomiting. You can access these weapons through a “weapon wheel” in a single action. In the multiplayer game, players can earn points and spend them on custom upgrades as they progress up the levels. Downloadable content will arrive as early as Oct. 4.

The single-player campaign game lasts an estimated six to eight hours. I’ve played the other Resistance games all the way through. I’m looking forward to finishing this one. In particular, I’m looking forward to some of the huge beasts you have to fight in the major boss battles of the game.